Bristle arrangement for brush seal, method and assembly for making same, and method of making brush seal

ABSTRACT

A bristle arrangement for use in a brush seal, comprising: a plurality of bristles arranged in a length; and a joint along the length securing the bristles together. The fixture for making the bristle arrangement, comprises: a base having a surface with an arrangement of guides thereon, the guides adapted to orient the tufts on the surface; and a cover having a surface for receiving the tufts. The cover removably mounts to the base to sandwich the tufts between the cover and the base. Making a brush seal with multiple stages comprises the steps of: providing plates and bristle arrangements; creating a stack of plates and bristle arrangements; and joining the stack.

TECHNICAL FIELD

[0001] The present invention relates to brush seals. Specifically, thepresent invention relates to a bristle arrangement for the brush seal,to a method and assembly for making the bristle arrangement, and to amethod of making the brush seal.

BACKGROUND OF THE INVENTION

[0002] Brush seals are commonly used to prevent the escape of fluid(i.e. air) through a gap between two parts. Brush seals are commonlyfound on gas turbine engines. In a turbine, the brush seals typicallyprevent secondary flow from escaping through a gap between a stationarypart (e.g. a diffuser case) and a rotating part (e.g. a turbine shaft).The brush seal has other uses, such as sealing a gap between stationaryparts.

[0003] A brush seal typically includes wire bundles sandwiched betweenplates. The plates and the wire bundles define one stage of the brushseal. To increase capability, a brush seal may have multiple stages. Themultiple stages allow a greater pressure drop across the brush seal fromthe upstream side to the downstream side.

[0004] Unfortunately, conventional assembly methods are not well suitedfor multiple stage brush seals. Specifically, conventional methodscannot concurrently assemble the multiple stages of a brush seal.Rather, conventional methods separately assemble each stage of the brushseal. A subsequent step in the conventional methods then combines thediscretely assembled stages to form the multiple stage brush seal.

DISCLOSURE OF THE INVENTION

[0005] It is an object of the present invention to provide a new andimproved method of making a brush seal.

[0006] It is a further object of the present invention to provide amethod of assembling a multiple stage brush seal with one set offixtures.

[0007] It is a further object of the present invention to provide amethod of assembling a brush seal that can concurrently build thevarious stages of a multiple stage brush seal.

[0008] It is a further object of the present invention to provide a newand improved brush seal made from fewer components.

[0009] It is a further object of the present invention to provide a newand improved bristle arrangement.

[0010] It is a further object of the present invention to provide abristle arrangement that secures together all of the bristles for onestage of the brush seal.

[0011] It is a further object of the present invention to provide a newand improved method for making the bristle arrangement.

[0012] It is a further object of the present invention to provide a newand improved fixture for making the bristle arrangement.

[0013] These and other objects of the present invention are achieved inone aspect by a bristle arrangement for use in a brush seal. The bristlearrangement comprises: a plurality of bristles arranged in a length; anda joint securing the plurality of bristles together. The joint extendsalong the length.

[0014] These and other objects of the present invention are achieved inanother aspect by method of making a bristle arrangement for a brushseal. The method comprises the steps of: arranging a plurality ofbristles along a length; and joining the plurality of bristles along thelength.

[0015] These and other objects of the present invention are achieved inanother aspect by apparatus for making a bristle arrangement. Theapparatus comprises: a base having a surface with an arrangement ofguides thereon, the guides adapted to orient a plurality of tufts on thesurface; and a cover having a surface for receiving the tufts. The coverremovably mounts to the base to sandwich the tufts between the cover andthe base.

[0016] These and other objects of the present invention are achieved inanother aspect by a method of making a brush seal having multiplestages. The method comprises the steps of: providing plates and bristlearrangements; creating a stack of plates and bristle arrangements todefine the multiple stages of the brush seal; and joining the stack tocreate the brush seal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other uses and advantages of the present invention will becomeapparent to those skilled in the art upon reference to the specificationand the drawings, in which:

[0018]FIG. 1a is a front view of a conventional multiple stage brushseal;

[0019]FIG. 1b is a cross-sectional view of the brush seal taken alongline IB-IB in FIG. 1a;

[0020]FIG. 1c is an exploded, cross-sectional view showing the variouscomponents of the brush seal of FIG. 1a;

[0021]FIG. 2 is a schematic of a conventional method of assembling amultiple stage brush seal;

[0022]FIG. 3a is a plan view of a bristle arrangement of the presentinvention;

[0023]FIG. 3b is a cross-sectional view of the bristle arrangement takenalong line IIIB-IIIB in FIG. 3a;

[0024]FIG. 4 is a cross-sectional view of a fixture used to assemble thebristle arrangement of FIGS. 3a and 3 b during an initial assembly step;

[0025]FIG. 5 is a cross-sectional view of the fully assembled fixture ata subsequent step of assembling the bristle arrangement of FIGS. 3a and3 b;

[0026]FIG. 6 is a plan view, with partial cut-away, of the fullyassembled fixture;

[0027]FIG. 7 is a plan view of the fixture at a subsequent step ofassembling the bristle arrangement of FIGS. 3a and 3 b;

[0028]FIG. 8 is a schematic of a method of assembling the bristleassembly of FIGS. 3a and 3 b using the fixture shown in FIGS. 4-7;

[0029]FIG. 9a is an exploded, cross-sectional view showing the variouscomponents of a multiple stage brush seal of the present invention;

[0030]FIG. 9b is a cross-sectional view of the fully assembled brushseal of the present invention; and

[0031]FIG. 10 is a schematic of a method of assembling the multiplestage brush seal of FIG. 9b.

BEST MODE FOR CARRYING OUT THE INVENTION

[0032]FIGS. 1a-1 c display a conventional multiple stage brush seal 50.Although the figures display a two stage brush seal, the brush seal 50could have more than two stages.

[0033] The brush seal 50 is an assembly of plates and bristles. FIG. 1cis an exploded view of all the various components that form the brushseal 50. The brush seal 50 includes a windage cover 51, side plates 53,back plates 55 and packs of bristles 63.

[0034] Each stage 59, 61 of the brush seal 50 comprises a pack ofbristles 63 located between a side plate 53 and a back plate 55. Thewindage cover 51 resides in front, i.e. upstream, of the stages 59, 61.

[0035]FIG. 2 schematically demonstrates a conventional method 100 ofassembling the multiple stage brush seal 50. The method 100 builds upthe brush seal 50 by stage. A first step 101 of the method 100 assemblesone such stage of the brush seal 50 within a fixture (not shown).

[0036] The operator assembles the brush seal stage as follows. Theoperator first places the back plate 55 within the fixture. Next, theoperator places tufts of bristles 63 on the back plate 55. The operatorthen places the side plate 53 over the bristles 63.

[0037] To complete the first step 101, the operator uses the fixture tosandwich the various components together. Ideally, the fixture clampsthe plates 53, 55 together to retain the bristles 63 therebetween. Thecomponents remain in the fixture for the next step of the conventionalmethod 100.

[0038] A second step 103 of the method 100 bonds the brush seal stagetogether, such as by welding the plates 53, 55 and the pack of bristles63. After bonding the components together, the operator can remove thebrush seal stage from the fixture.

[0039] A third step 105 determines if the brush seal 50 requires theassembly of another stage. If the brush seal 50 requires another stage,the method 100 returns to the first step 101 to produce another stage.If the operator has assembled sufficient stages, the method 100continues to the next step.

[0040] A fourth step 107 assembles the various stages 59, 61 of thebrush seal 50 within another fixture (not shown). For example, theoperator first places the second stage 61 within the fixture. Theoperator then places the first stage 59 in the fixture. Finally, theoperator places the windage cover 51 over the stages 59, 61. Now builtup, the operator secures these sub-assemblies together using thefixture.

[0041] A fifth step 109 of the method 100 bonds the sub-assembliestogether, such as by welding. Once bonded together, the operator canremove the brush seal 50 from the fixture.

[0042] A clear drawback of the conventional method 100 is therequirement to build-up the brush seal stage by stage. Another drawbackof the conventional method 100 is the number of components forming thebrush seal 50. The two stage brush seal 50 shown in FIGS. 1a-1 crequires one windage cover 51, two side plates 53, two back plates 55and two packs of bristles 63.

[0043] The present invention avoids these drawbacks. FIGS. 3a-10 will beused to describe the present invention.

[0044]FIGS. 3a and 3 b display a bristle arrangement 200 of the presentinvention. The bristle arrangement 200 includes a plurality of bristles201 secured together by ajoint 203. The bristles 201 could be made fromany suitable metallic material, preferably a 0.002″, 0.003″, 0.004 or0.006″ diameter cobalt alloy wire.

[0045] As seen in FIG. 3a, the joint 203 extends continuously along theouter diameter of the circular bristle arrangement 200. Preferably, theoperator produces the joint 203 by welding the bristles 201 together.The operator, however, could use other methods to produce the joint 203.As will become clear below, the bristle arrangement 200 defines onestage of bristles in the brush seal 50.

[0046] Different shapes of the bristle arrangement 200 are possible.Rather than the annular shape shown in FIGS. 3a and 3 b, the bristlearrangement 200 could be arcuate (not shown) or linear (not shown). Infact, the bristle arrangement 200 could have any other shape (notshown). Regardless of the specific shape, the joint 203 should extendalong an entire length of the bristle arrangement 200 to retain all ofthe bristles 201 together.

[0047] FIGS. 4-9 display a fixture 300 used to make the bristlearrangement 200. The fixture 300 includes a shuttle 301, a base 303, anda cover 305.

[0048] The shuttle 301 receives the base 303 and the cover 305. Theshuttle 301 has a bottom wall 307 and a side wall 309 extendingtherefrom. To create the circular bristle arrangement 200 shown in FIG.3, the bottom wall 307 and the side wall 309 are preferably circular.The side wall 309 defines the perimeter of the shuttle 301.

[0049] An upper end of the side wall 309 includes an annular shoulder311. A plurality of guides 313 extend from the annular shoulder 311. Theguides 313 could be, for example, spring pins or piano wire. Asdescribed in more detail below, the guides 313 help the operator placethe bristles in the fixture 300. Alternatively, the shoulder 311 couldhave slots (not shown) therein to receive the bristles.

[0050] The base 303 fits within the perimeter of the shuttle 301, asseen in FIG. 5. Preferably, the base 303 is removable from the shuttle301. Ideally, the base 303 sits within the shuttle 301 without usingfasteners.

[0051] When placed within the shuttle 301, an upper surface 315 of thebase 303 is flush with a bottom surface 317 of the shoulder 311. Aplurality of guides 319 also extend from the upper surface 315 of thebase 303. The guides 319, like guides 313, could be spring pins, pianowire or any other suitable arrangement. The guides 319 also help theoperator place the bristles in the fixture 300. Alternatively, thesurface 315 could have slots (not shown) therein to receive thebristles.

[0052] The operator adds bristle tufts 321 to the fixture 300 as seen inFIGS. 4-6. The tuft 321 is a group of bristles 325 (e.g. 0.002″, 0.003,0.004 or 0.006″ diameter Cobalt wire) held together by a bead 323.Preferably, the operator has previously formed the tufts 321 usingconventional techniques.

[0053] The operator places each tuft 321 between adjacent guides 313,319 in the shuttle 301 and the base 303. As seen in FIG. 6, the operatorplaces the tufts 321 in the fixture 300 in a skewed fashion relative toa line extending radially from the center of the fixture 300. In otherwords, the bristles extend at an angle a to the radial line. The angle aorients the bristles 325 in the direction that the rotating part of theengine rotates.

[0054] As seen in FIG. 4, the beads 323 of the tufts 321 reside to theoutside of the fixture 300. For this arrangement, the operator placesthe beads 323 of the tufts 321 against the annular shoulder 311 of theside wall 309. The operator could, however, arrange the tufts 321 in anyother suitable orientation.

[0055] Although described as a manual process, the present inventioncould use automated equipment (not shown) to place the tufts 321 in thefixture 300. Regardless of the placement method, the operator places thecover 305 on the fixture 300 upon placing all of the tufts 321. FIG. 5displays the fixture 300 with the cover 305 thereon.

[0056] The shape of the cover 305 resembles the base 303. The cover 305includes a bottom surface 331 that abuts portions of the upper surface315 of the base 303. The bottom surface 331 also includes a recess 333which, when the cover 305 is on the base 303, creates a receiving areafor the tufts 321 and for the guides 319.

[0057] Fasteners 335 secure the cover 305 to the base 303. The operatorpreferably tightens the fasteners 335 with a torque sufficient to spreadapart the bristles 325 in a uniform fashion around the fixture 300.

[0058] Next, the operator removes the base 303 and cover 305 (containingthe tufts 321 sandwiched therebetween) from the shuttle 301. Theoperator could remove the base 303 and cover 305 by grasping eyebolts339 or any other suitable feature. FIG. 7 displays the base 303 andcover 305 removed from the shuttle 301.

[0059] As seen in FIG. 7, removing the base 303 and cover 305 from theshuttle 201 exposes a portion of the tufts 321 (i.e. the beads 323 and aportion of the bristles 325). The operator can now join together all thebristles 325 at the exposed portions.

[0060] Preferably, the operator welds the bristles 325 together with asuitable welding machine, such as a laser welder, a tungten inert gas(TIG) welder, or an electron beam (EB) welder. However, the presentinvention could use other suitable techniques to join the bristles 325together.

[0061] At this point, the operator can remove the cover 305 from thebase 303 to reveal the result of the aforementioned steps. The result isthe bristle arrangement 200 shown in FIGS. 3a and 3 b. Being annular,one could refer to the bristle arrangement 200 in the figures as abristle ring.

[0062]FIG. 8 schematically summarizes the aforementioned method ofmaking the bristle arrangement 200. The figure provides a method 400that includes a first step 401 of assembling the fixture 300. Asdiscussed earlier, the operator places the base 303 in the shuttle 301to accomplish the first step 401.

[0063] The operator arranges the tufts 321 in the fixture 300 during asecond step 403. As seen in FIG. 6, the tufts 321 form an annulus. Asdiscussed earlier, the operator could arrange the tufts 321 to any othershape (e.g. in an arc or in a line).

[0064] The operator then secures the cover 305 to the fixture 300 duringa third step 405. Tightening the fasteners 335 spreads the bristles 325in a uniform fashion around the fixture 300.

[0065] The operator then removes the base 303 and cover 305 (with thetufts 321 sandwiched therebetween) from the shuttle 301 during a fourthstep 407.

[0066] The operator then joins the bristles 325 together during a fifthstep 409. The operator preferably welds the bristles 325 together. Theresult of the method 400 is the bristle ring 200.

[0067] The operator can easily handle the bristle ring 200 of thepresent invention. The bristle ring 200 is now one-piece since the joint203 secures all of the bristles 201 together. Use of the one-piecebristle ring 200 is easier than the conventional method 100. Theconventional method 100 of assembling the brush seal 50 requires themanipulation of a plurality of discrete tufts.

[0068] Using the bristle ring 200 of the present invention also allowsthe operator to build multiple brush seal stages concurrently. In fact,the present invention allows the operator to build all stages of thebrush seal concurrently. FIGS. 9a and 9 b display a multiple stage brushseal 500 assembled with bristle rings 200 of the present invention. FIG.10 schematically demonstrates a method 600 of assembling the brush seal500.

[0069] In a first step 601, the operator assembles all of the componentsof the brush seal 500 within a fixture (not shown). The operator firstplaces a back plate 501 in the fixture. The operator then places a firstbristle ring 200 on the back plate.

[0070] Next, the operator places a middle plate 503 over the bristlering 200. Comparing the brush seal 500 and the brush seal 50 in FIG. 1c,the one-piece middle plate 503 of the brush seal 500 equates to both theside plate 53 and the back plate 55 of the conventional brush seal 50.The operator can utilize the single middle plate 503 since the presentinvention does not build up the brush seal stages discretely. Rather,the present invention assembles the brush seal 500 in one step.

[0071] The operator then places a second bristle ring 200 over themiddle plate 503. Finally, the operator places a windage cover 505 overthe middle plate 503. Comparing the brush seal 500 and the brush seal 50in FIG. 1c, the one-piece windage cover 505 of the brush seal 500equates to both the side plate 53 and the windage cover 51 of theconventional brush seal 50. Again, the operator can utilize the singlewindage cover 505 because the present invention does not build up thebrush seal stages discretely. Rather, the present invention assemblesthe brush seal 500 in one step.

[0072] The operator uses the fixture to hold these components togetherfor the next step of the method 600.

[0073] A second step 603 of the method 600 bonds the entire brush seal500 together at one time. Preferably, the operator fusion welds thecomponents 501, 200, 503, 200, 505 together. The operator could use thesame welder as used in the sixth step 411 of the bristle ring assemblymethod 400. If needed, the welder could provide filler material duringthis second step 603.

[0074] Once bonded, the operator can remove the brush seal 500 from thefixture.

[0075] The result of the method 600 is the brush seal 500 of FIGS. 11aand 11 b. Although described with reference to multiple stage brushseals 500, the bristle ring 200 of the present invention could also beused in single stage brush seals (not shown).

[0076] The brush seal is ultimately installed in the engine. Dependingupon the rotation direction of the engine, the operator can either placethe bristle ring 200 in the fixture for clockwise or forcounterclockwise rotation. The operator merely flips the bristle ring200 over to change the rotation direction.

[0077] The present invention has been described in connection with thepreferred embodiments of the various figures. It is to be understoodthat other similar embodiments may be used or modifications andadditions may be made to the described embodiment for performing thesame function of the present invention without deviating therefrom.Therefore, the present invention should not be limited to any singleembodiment, but rather construed in breadth and scope in accordance withthe recitation of the appended claims.

What is claimed is:
 1. A bristle arrangement for use in a brush seal,the bristle arrangement comprising: a plurality of bristles arranged ina length; and a joint securing said plurality of bristles together;wherein said joint extends along said length.
 2. The bristle arrangementas recited in claim 1, wherein said joint is a weld joint.
 3. Thebristle arrangement as recited in claim 1, wherein said bristles eachhave opposed ends, and said joint is located at one of said opposedends.
 4. The bristle arrangement as recited in claim 1, wherein saidplurality of bristles are metallic.
 5. The bristle arrangement asrecited in claim 1, wherein the bristle arrangement is subsequentlycombined with plates to form a brush seal.
 6. The bristle arrangement asrecited in claim 5, wherein a plurality of the bristle arrangements aresubsequently combined with a plurality of said plates to form a multiplestage brush seal.
 7. The bristle arrangement as recited in claim 1,wherein said length defines an arc.
 8. The bristle arrangement asrecited in claim 7, wherein said arc is a circle.
 9. The bristlearrangement as recited in claim 7, wherein said arc has an outerdiameter and an inner diameter, and said joint is located at said outerdiameter or said inner diameter.
 10. The bristle arrangement as recitedin claim 1, wherein said joint is continuous.
 11. The bristlearrangement as recited in claim 1, wherein said plurality of bristlesare grouped in tufts, said joint securing said tufts together.
 12. Amethod of making a bristle arrangement for a brush seal, comprising thesteps of: arranging a plurality of bristles along a length; and joiningsaid plurality of bristles along said length.
 13. The method as recitedin claim 12, wherein the joining step comprises welding.
 14. The methodas recited in claim 12, wherein the joining step occurs at an end ofsaid bristles.
 15. The method as recited in claim 12, wherein saidplurality of bristles are metallic.
 16. The method as recited in claim12, further comprising the step of securing the bristle arrangementbetween plates to form a brush seal.
 17. The method as recited in claim12, wherein said length comprises an arc.
 18. The method as recited inclaim 17, wherein said arc is a circle.
 19. The method as recited inclaim 17, wherein the joining step occurs at an outer diameter or aninner diameter of said arc.
 20. The method as recited in claim 17,wherein the joining step creates a continuous joint along said arc. 21.The method as recited in claim 12, wherein the arranging step comprisesthe steps of: separating said plurality of bristles into groups; joiningsaid plurality of bristles within said groups to create tufts; andarranging said tufts along said length.
 22. An apparatus for making abristle arrangement, comprising: a base having a surface with anarrangement of guides thereon, said guides adapted to orient a pluralityof tufts on said surface; and a cover having a surface for receiving thetufts; wherein said cover removably mounts to said base to sandwich saidplurality of tufts between said base and said cover.
 23. The apparatusas recited in claim 23, further comprising a shuttle, said shuttleremovably receiving said base and having an arrangement of guidesthereon corresponding to said guides on said base for orienting saidtufts.
 24. A method of making a brush seal having multiple stages,comprising the steps of: providing plates and bristle arrangements;creating a stack of said plates and bristle arrangements to define saidmultiple stages of said brush seal; and joining said stack to createsaid brush seal.
 25. The method as recited in claim 24, wherein saidbristle arrangement includes: a plurality of bristles arranged along alength; and a joint extending along said length and securing saidplurality of bristles together.
 26. The method as recited in claim 25,wherein said plurality of bristles are arranged in an arc, and saidjoint extends along said arc.
 27. The method as recited in claim 26,wherein said arc is a circle.
 28. The method as recited in claim 25,wherein said joint extends continuously along said length.
 29. Themethod as recited in claim 24, wherein the joining step compriseswelding.
 30. The method as recited in claim 29, wherein said platesinclude a windage cover.
 31. The method as recited in claim 24, whereinsaid plates and said bristle arrangements are discrete before the stackcreating step.